Use has been made of mechanisms having a great height and a large rotating counterpoise for moving the plungers of pumps operating under the above conditions, since generally speaking the length of travel of said piston or plunger is considerable.
The well-known "Perry" Manual shows the reason why it is advisable to use pumps with one or more cylinders or pistons, when it is necessary to work under the above-mentioned conditions: plunger pumps are the only ones which can operate in the range from 0 to 400 meters with an almost continuous discharge of about 520 liters per minute, under atmospheric conditions. The rotating counterpoise devices or mechanism, apart from being extremely expensive, are also difficult to install, and even more difficult to transport, since the masses which help to counter-balance the forces acting on the piston or plunger are considerable. Again, these rotating masses, being extremely heavy in relation to the weight of the rest of the equipment, require a whole structure and anchoring of appreciable size, and in addition their speed of rotation is necessarily low.